<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"> 
<title>css3基础</title> 
<style> 
.button {
    background-color: #4CAF50;
    border: none;
    color: white;
    padding: 15px 32px;
    text-align: center;
    text-decoration: none;
    display: inline-block;
    font-size: 16px;
    margin: 4px 2px;
    cursor: pointer;
}
.button1 {border-radius: 2px;}
.button2 {border-radius: 4px;}
.button3 {border-radius: 8px;}
.button4 {border-radius: 12px;}
.button5 {border-radius: 50%;}
</style>
</head>
<body>
<button>默认按钮</button>
<a href="#" class="button">链接按钮</a>
<button class="button">css按钮</button>
<input type="button" class="button" value="输入框按钮">
<br>
<br>
<buttom class="button button1">2px</buttom>
<buttom class="button button2">4px</buttom>
<buttom class="button button3">8px</buttom>
<buttom class="button button4">12px</buttom>
<buttom class="button button5">50px</buttom>
</body>
</html>